In the words of the submitter:

---------
Make callers of namei() responsible for releasing references or locks
instead of having the underlying filesystems do it.  This eliminates
redundancy in all terminal filesystems and makes it possible for stacked
transport layers such as umapfs or nullfs to operate correctly.

Quality testing was done with testvn, and lat_fs from the lmbench suite.

Some NFS client testing courtesy of Patrik Kudo.

vop_mknod and vop_symlink still release the returned vpp.  vop_rename
still releases 4 vnode arguments before it returns.  These remaining cases
will be corrected in the next set of patches.
---------

Submitted by:	Michael Hancock <michaelh@cet.co.jp>

2 files changed, 26 insertions, 44 deletions

diff --git a/sys/gnu/ext2fs/ext2_vnops.c b/sys/gnu/ext2fs/ext2_vnops.c
index f533012..21068e4 100644
--- a/sys/gnu/ext2fs/ext2_vnops.c
+++ b/sys/gnu/ext2fs/ext2_vnops.c
@@ -301,11 +301,6 @@ ext2_remove(ap)
 		ip->i_flag |= IN_CHANGE;
 	}
 out:
-	if (dvp == vp)
-		vrele(vp);
-	else
-		vput(vp);
-	vput(dvp);
 	return (error);
 }
 
@@ -367,7 +362,6 @@ out1:
 	if (tdvp != vp)
 		VOP_UNLOCK(vp, 0, p);
 out2:
-	vput(tdvp);
 	return (error);
 }
 
@@ -480,7 +474,15 @@ abortit:
 #endif
 			return (ENOENT);
 		}
-		return (VOP_REMOVE(fdvp, fvp, fcnp));
+		error = VOP_REMOVE(fdvp, fvp, fcnp);
+		/* XXX - temporarily preserve previous behavior */
+		if (fdvp == fvp)
+			vrele(fdvp);
+		else
+			vput(fdvp);
+		if (fvp != NULLVP)
+			vput(fvp);
+		return (error);
 	}
 	if (error = vn_lock(fvp, LK_EXCLUSIVE, p))
 		goto abortit;
@@ -873,7 +875,6 @@ ext2_mkdir(ap)
 			zfree(namei_zone, cnp->cn_pnbuf);
 			UFS_VFREE(tvp, ip->i_number, dmode);
 			vput(tvp);
-			vput(dvp);
 			return (error);
 		}
 #endif
@@ -886,7 +887,6 @@ ext2_mkdir(ap)
 		zfree(namei_zone, cnp->cn_pnbuf);
 		UFS_VFREE(tvp, ip->i_number, dmode);
 		vput(tvp);
-		vput(dvp);
 		return (error);
 	}
 #endif
@@ -957,7 +957,6 @@ bad:
 		*ap->a_vpp = tvp;
 out:
 	zfree(namei_zone, cnp->cn_pnbuf);
-	vput(dvp);
 	return (error);
 #undef  DIRBLKSIZ
 #define DIRBLKSIZ  DEV_BSIZE
@@ -977,6 +976,7 @@ ext2_rmdir(ap)
 	struct vnode *vp = ap->a_vp;
 	struct vnode *dvp = ap->a_dvp;
 	struct componentname *cnp = ap->a_cnp;
+	struct proc *p = cnp->cn_proc;
 	struct inode *ip, *dp;
 	int error;
 
@@ -1011,8 +1011,7 @@ ext2_rmdir(ap)
 	dp->i_nlink--;
 	dp->i_flag |= IN_CHANGE;
 	cache_purge(dvp);
-	vput(dvp);
-	dvp = NULL;
+	VOP_UNLOCK(dvp, 0, p);
 	/*
 	 * Truncate inode.  The only stuff left
 	 * in the directory is "." and "..".  The
@@ -1025,13 +1024,10 @@ ext2_rmdir(ap)
 	 * worry about them later.
 	 */
 	ip->i_nlink -= 2;
-	error = UFS_TRUNCATE(vp, (off_t)0, IO_SYNC, cnp->cn_cred,
-	    cnp->cn_proc);
+	error = UFS_TRUNCATE(vp, (off_t)0, IO_SYNC, cnp->cn_cred, p);
 	cache_purge(ITOV(ip));
+	vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
 out:
-	if (dvp)
-		vput(dvp);
-	vput(vp);
 	return (error);
 }
 
@@ -1098,7 +1094,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 	error = UFS_VALLOC(dvp, mode, cnp->cn_cred, &tvp);
 	if (error) {
 		zfree(namei_zone, cnp->cn_pnbuf);
-		vput(dvp);
 		return (error);
 	}
 	ip = VTOI(tvp);
@@ -1146,7 +1141,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 			zfree(namei_zone, cnp->cn_pnbuf);
 			UFS_VFREE(tvp, ip->i_number, mode);
 			vput(tvp);
-			vput(dvp);
 			return (error);
 		}
 #endif
@@ -1159,7 +1153,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 		zfree(namei_zone, cnp->cn_pnbuf);
 		UFS_VFREE(tvp, ip->i_number, mode);
 		vput(tvp);
-		vput(dvp);
 		return (error);
 	}
 #endif
@@ -1188,7 +1181,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 
 	if ((cnp->cn_flags & SAVESTART) == 0)
 		zfree(namei_zone, cnp->cn_pnbuf);
-	vput(dvp);
 	*vpp = tvp;
 	return (0);
 
@@ -1198,7 +1190,6 @@ bad:
 	 * or the directory so must deallocate the inode.
 	 */
 	zfree(namei_zone, cnp->cn_pnbuf);
-	vput(dvp);
 	ip->i_nlink = 0;
 	ip->i_flag |= IN_CHANGE;
 	vput(tvp);
diff --git a/sys/gnu/fs/ext2fs/ext2_vnops.c b/sys/gnu/fs/ext2fs/ext2_vnops.c
index f533012..21068e4 100644
--- a/sys/gnu/fs/ext2fs/ext2_vnops.c
+++ b/sys/gnu/fs/ext2fs/ext2_vnops.c
@@ -301,11 +301,6 @@ ext2_remove(ap)
 		ip->i_flag |= IN_CHANGE;
 	}
 out:
-	if (dvp == vp)
-		vrele(vp);
-	else
-		vput(vp);
-	vput(dvp);
 	return (error);
 }
 
@@ -367,7 +362,6 @@ out1:
 	if (tdvp != vp)
 		VOP_UNLOCK(vp, 0, p);
 out2:
-	vput(tdvp);
 	return (error);
 }
 
@@ -480,7 +474,15 @@ abortit:
 #endif
 			return (ENOENT);
 		}
-		return (VOP_REMOVE(fdvp, fvp, fcnp));
+		error = VOP_REMOVE(fdvp, fvp, fcnp);
+		/* XXX - temporarily preserve previous behavior */
+		if (fdvp == fvp)
+			vrele(fdvp);
+		else
+			vput(fdvp);
+		if (fvp != NULLVP)
+			vput(fvp);
+		return (error);
 	}
 	if (error = vn_lock(fvp, LK_EXCLUSIVE, p))
 		goto abortit;
@@ -873,7 +875,6 @@ ext2_mkdir(ap)
 			zfree(namei_zone, cnp->cn_pnbuf);
 			UFS_VFREE(tvp, ip->i_number, dmode);
 			vput(tvp);
-			vput(dvp);
 			return (error);
 		}
 #endif
@@ -886,7 +887,6 @@ ext2_mkdir(ap)
 		zfree(namei_zone, cnp->cn_pnbuf);
 		UFS_VFREE(tvp, ip->i_number, dmode);
 		vput(tvp);
-		vput(dvp);
 		return (error);
 	}
 #endif
@@ -957,7 +957,6 @@ bad:
 		*ap->a_vpp = tvp;
 out:
 	zfree(namei_zone, cnp->cn_pnbuf);
-	vput(dvp);
 	return (error);
 #undef  DIRBLKSIZ
 #define DIRBLKSIZ  DEV_BSIZE
@@ -977,6 +976,7 @@ ext2_rmdir(ap)
 	struct vnode *vp = ap->a_vp;
 	struct vnode *dvp = ap->a_dvp;
 	struct componentname *cnp = ap->a_cnp;
+	struct proc *p = cnp->cn_proc;
 	struct inode *ip, *dp;
 	int error;
 
@@ -1011,8 +1011,7 @@ ext2_rmdir(ap)
 	dp->i_nlink--;
 	dp->i_flag |= IN_CHANGE;
 	cache_purge(dvp);
-	vput(dvp);
-	dvp = NULL;
+	VOP_UNLOCK(dvp, 0, p);
 	/*
 	 * Truncate inode.  The only stuff left
 	 * in the directory is "." and "..".  The
@@ -1025,13 +1024,10 @@ ext2_rmdir(ap)
 	 * worry about them later.
 	 */
 	ip->i_nlink -= 2;
-	error = UFS_TRUNCATE(vp, (off_t)0, IO_SYNC, cnp->cn_cred,
-	    cnp->cn_proc);
+	error = UFS_TRUNCATE(vp, (off_t)0, IO_SYNC, cnp->cn_cred, p);
 	cache_purge(ITOV(ip));
+	vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, p);
 out:
-	if (dvp)
-		vput(dvp);
-	vput(vp);
 	return (error);
 }
 
@@ -1098,7 +1094,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 	error = UFS_VALLOC(dvp, mode, cnp->cn_cred, &tvp);
 	if (error) {
 		zfree(namei_zone, cnp->cn_pnbuf);
-		vput(dvp);
 		return (error);
 	}
 	ip = VTOI(tvp);
@@ -1146,7 +1141,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 			zfree(namei_zone, cnp->cn_pnbuf);
 			UFS_VFREE(tvp, ip->i_number, mode);
 			vput(tvp);
-			vput(dvp);
 			return (error);
 		}
 #endif
@@ -1159,7 +1153,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 		zfree(namei_zone, cnp->cn_pnbuf);
 		UFS_VFREE(tvp, ip->i_number, mode);
 		vput(tvp);
-		vput(dvp);
 		return (error);
 	}
 #endif
@@ -1188,7 +1181,6 @@ ext2_makeinode(mode, dvp, vpp, cnp)
 
 	if ((cnp->cn_flags & SAVESTART) == 0)
 		zfree(namei_zone, cnp->cn_pnbuf);
-	vput(dvp);
 	*vpp = tvp;
 	return (0);
 
@@ -1198,7 +1190,6 @@ bad:
 	 * or the directory so must deallocate the inode.
 	 */
 	zfree(namei_zone, cnp->cn_pnbuf);
-	vput(dvp);
 	ip->i_nlink = 0;
 	ip->i_flag |= IN_CHANGE;
 	vput(tvp);